Thrombectomy and stenting system

ABSTRACT

A design capable of both mechanical thrombectomy and stenting for treating occlusions in the cerebral vasculature provides for a three-catheter setup. The first outer catheter has the largest diameter and can serve as a guide catheter while also being a sheath for the other catheters. The second deployment catheter can be configured for the aspiration of occlusions and can include a stepped or recessed section proximal of the distal tip that can act as a housing for a braided expandable stent. The outer diameter of this stepped section can be lined with an inflation device on top of which the braided stent sits. Internal to the second deployment catheter is a microcatheter which can deliver mechanical thrombectomy devices to the target site to retrieve an occlusion in the vessel, after which the stent can be expanded and implanted in the vessel.

FIELD OF THE INVENTION

The present invention generally relates devices and methods used inremoving obstructions and treating stenosis in the cerebral bloodvessels during intravascular medical treatments. More specifically, thepresent invention relates to a multi-catheter system for bringingtogether the procedures of mechanical thrombectomy and stenting.

BACKGROUND

Atherosclerosis results from lesions which narrow and reduce the spacein the lumen of vessels in the vasculature. Such lesions are usuallycomposed of plaque, which can be fat, cholesterol, calcium, or othercomponents of the blood. Severe occlusion or closure can impede the flowof oxygenated blood to different organs and parts of the body and resultin other cardiovascular disorders such as heart attack or stroke.Narrowing of vessels, or stenosis, increases the risk that clots andother emboli can lodge at such locations, especially in theneurovascular where vessel diameters are already small. Intracranialatherosclerotic disease (ICAD) is the narrowing of those arteries andvessels supplying blood to the brain and represents the most commonproximate mechanism of ischemic stroke.

Treatment for vascular occlusions are well known in the art. Methods caninclude utilizing drugs, such as anticoagulants or anti-platelet agents,as well as medical procedures such as surgical endarterectomy,angioplasty, and stenting. Much of the recent success in endovascularrevascularization treatments (ERT) has been the further development ofsafe thrombectomy devices. Devices such as stentrievers,direct-aspiration systems, and other clot retrieval devices have beenstrongly associated with better clinical outcomes. However, thesedevices are primarily designed to recanalize the vessel by removing andretrieving an occluding embolus. Sufficient recanalization may not occurif there is also significant stenosis present at the occlusion site,increasing the need for implanted stents.

Treatment methods for addressing clots and lesions in the neurovascularin particular depend on the degree of stenosis, the shape of the targetocclusion site (i.e. truncal, branching, etc.), and the patient'soverall condition. Mechanical procedures often involve using medicaldevices to retrieve an occlusive clot and then utilizing balloons andstents to open a narrowed artery. Following the use of a stentriever orother clot retrieval device, a balloon is delivered to a target site andinflated to dilate the stenosis. The balloon can then be removed andexchanged through a catheter for a stent delivery device. If desirable,once the stent is in place a balloon can be inflated inside the stent topress the struts of the stent frame firmly against the inner wall of thevessel.

However, various significant challenges exist in interpreting anddiagnosing the stenosis in the first place. This is especially in thevery small and tortuous vessels of the cerebral vasculature. During thetreatment of stroke or transient ischemic attack, it can be unknown ifthe occlusion is the result of a blood clot alone of if a stenosis isalso present. Identifying stenotic lesions can be arduous because it isdifficult to differentiate them from clots and other embolism-relatedocclusions through baseline angiography. In many cases the presence ofthe stenosis is only identified after initial treatment options arechosen and an ERT procedure is already underway, and the devices andmethods used to remove occlusions are often different from those used totreat stenosis and stent a vessel.

In cases where both a blood clot and stenosis are present, the physiciancan often be required to change out catheters, devices, and oftenguidewires after removing the clot. Devices offering proceduralflexibility are thus highly valuable, as the need for multiple passesand device deliveries can be cumbersome and these mechanical treatmentsfurther create the potential of releasing additional fragments into thevasculature. Such fragments can include but are not limited to bloodclots, plaque, and other thrombi debris.

The need for shorter door-to-procedure times in is always present tolimit lasting damage in ischemic stroke patients. Therefore, thereremains a need for new systems and devices to continue to address andimprove these treatments. The present design is aimed at providing animproved system and method for treating the combined presence of clotsand stenosis in the cerebral vasculature which addresses theabove-stated deficiencies.

SUMMARY

It is an object of the present design to provide systems, devices, andmethods to meet the above-stated needs. Generally, the proposed systemprovides for a three-catheter setup. The first catheter has the largestdiameter and can serve as a guide catheter while also being a deploymentsheath for the other catheters. The second catheter can be configuredfor aspiration and can include a stepped or recessed section proximal ofthe distal tip that can serve as a housing for a braided expandablestent. The outer diameter of this stepped section can be lined with aballoon or other inflatable member on top of which the flexible stentsits. Internal to the second catheter is a microcatheter which candeliver mechanical thrombectomy devices to the target site to retrievean occlusion in the vessel.

An example system for removing a clot from and stenting a blood vesselcan include a sheath member, a deployment catheter, and a microcatheter.The three catheters can be substantially concentric. A source can beconfigured to aspirate the internal lumen of the sheath member and/ordeployment catheter. The deployment catheter can have a lumen and anouter surface and be disposed within the lumen of the sheath member. Thedeployment catheter can have a flexible distal portion and a recessedregion on its outer surface with an outer diameter less than the outerdiameter of the deployment catheter in a region adjacent to the recessedregion. The flexible region can enhance deliverability and encompass thedistalmost region of the deployment catheter. For example, the flexibleregion could extend 15-30 centimeters proximal of the distal tip.

An inflation device and a stenting device can circumscribe the recessedregion of the deployment catheter outer surface. The recessed region canprovide a seat for the inflation and stenting devices on the outersurface and provide for a more low-profile system. The stenting devicecould be self-expandable, or the inflation device can be used to expandthe stenting device in a stenotic lesion and implant it as a stent,similar to traditional methods for balloon angioplasty known in the art.Inflation could be accomplished by utilizing an inflation lumen whichcould run the length of the deployment catheter. The inflation devicecould also be used to dilate the vessel during any part of the stentingprocedure.

For retrieval of obstructions in vessels, the system can be used as anaspiration catheter utilizing suction to remove an occlusive clot. Insituations where a clot has become lodged in a vessel or a region ofconstricted stenosis, the system can retrieve the clot by aspirating theclot in to the lumen of the deployment catheter, or by utilizing othermechanical thrombectomy procedures. For example, the third catheter ofthe system can be a microcatheter situated in the lumen of thedeployment catheter and configured to deliver a mechanical thrombectomydevice to a target occlusion. The mechanical thrombectomy device can beany of a number of commercially-available designs. In one example, anexpandable clot retriever which has a collapsed configuration inside themicrocatheter but self-expands into an enlarged deployed configurationupon exiting the lumen at the distal tip. The clot engaging portion ofthe device can have expandable members which can create a flow lumenacross an occlusion when deployed, while also having a plurality ofstruts which imbed to provide a strong grip on the clot for the initialstep of disengaging the clot from the vessel. To then remove the clot,the device could be retracted proximally into the deployment catheterwith aspiration. The device and clot can then either be withdrawn fromthe patient through the lumen of the catheter or can be drawn back farenough to lodge a firmer clot in the tip of a larger catheter to bewithdrawn in tandem with the catheter.

In another example, a thrombectomy and stenting system for removing aclot from a blood vessel and stenting the blood vessel can include asheath member, a deployment catheter situated in the lumen of the sheathmember, and a microcatheter situated in the lumen of the deploymentcatheter. The sheath member, deployment catheter, and microcatheter canbe concentric with one another and configured to move independentlyalong a longitudinal axis of the system. An expandable stenting devicecan be coupled to an outer surface of the deployment catheter. Themicrocatheter can contain a clot retrieval device for capturing andremoving the clot from the vessel.

The body of the stenting device can have a braided or interlinkingpattern with a matrix of sufficient density to support the walls of thevessel when implanted. The mesh tube of the stent can be ofmedical-grade stainless steel, such as 316 SS, or a cobalt orcobalt-chrome alloy. In other examples, the stent can be of polymeric orpartial-polymeric construction. The mesh braid could also be made from ashape-memory allow such that it self-expands upon deployment. The stentcan be bare metal, or the material can be coated with anon-pharmacological coating such as silicon carbide, carbon, andtitanium-nitride-oxide. In other cases, stents have been coated withbiodegradable, drug-eluting coatings designed to inhibit restenosis.These coatings could be anti-platelet or anti-coagulative agents to helpprevent clot formation after the procedure.

In one example, a portion of the deployment catheter outer surface cancontain a depressed region having a dimension that is less than adimension of another region of the deployment catheter adjacent to thedepressed region. The depressed region can be formed integrally with thebody of the deployment catheter, such as a notch or groove cut in to theouter surface of the deployment catheter. For example, if the supportingstructure for the deployment catheter is formed from a hypotube, thedepressed region could be laser cut into the outer surface. Furtherfeatures could also be cut in to the surface to improve flexibility andtrackability of the catheter. The expandable stenting member can besized so that the member is situated on or housed in the depressedregion. In some cases, the system can also have an inflation devicewhich is circumscribed with the stenting device on the outer surface ofthe deployment catheter. When the user wishes to implant a stent in aregion of stenosis, the sheath member can be withdrawn to expose thestenting device. The inflation device can then be inflated to expand thestenting device scaffolding and exert a radial force on the walls of thevessel.

Also provided is a method for using a system offering the flexibility ofboth mechanical thrombectomy and stenting procedures. The method canhave some or all of the following steps and variations thereof, and thesteps are recited in no particular order. A patient's vasculature isaccessed using conventionally-known techniques. A sheath member ispositioned approximate a stenotic lesion and occlusive clot. Adeployment catheter is disposed within the lumen of the sheath member. Amicrocatheter containing a thrombectomy device is positioned in thelumen of the deployment catheter. A stenting device comprising aninflation device and a stent is positioned on an outer surface of thedeployment catheter approximate the distal end of the catheter. Anaspiration source, such as a vacuum pump or syringe, is configured todirect aspiration through the lumen flow path of one or both of thesheath member and deployment catheter. Aspiration can be utilized bothfor clot retrieval and for preventing additional embolization.

The microcatheter and thrombectomy device are extended towards andacross the occlusive lot while maintaining the sheath, deploymentcatheter, and the stenting device approximate the lesion. The clot canbe aspirated through the lumen of the deployment catheter. The clot iscaptured by deploying the thrombectomy device from the microcatheter bymaintaining the position of the thrombectomy device across the clot andretracting the microcatheter proximally. The microcatheter andthrombectomy device with the captured clot can then be withdrawn intothe lumen of the deployment catheter. Alternatively, the sheath member,deployment catheter, and stenting device can be advanced over thethrombectomy device to cross and align with the stenosis. Once inposition, the sheath member can be retracted proximal of the lesion toexpose the stenting device.

The inflation device of the stenting device can be inflated, radiallyexpanding both the inflation device and stent across the lesion. Thisradial expansion can increase the diameter of a first portion of thevascular comprising the lesion to at least 75% of the diameter of asecond portion of the vascular adjacent to the first portion. Thisprocess opens the vessel and reduces the narrowing/occlusion caused bythe stenosis. Once the desired expansion is achieved, the stent can bereleased in place as an implant by deflating the inflation device. Oncethe stent is in place, the remainder of the system can be withdrawn fromthe patient.

Having the flexibility to conduct mechanical thrombectomy and stentingoperations with a single system, such as the current design, can greatlyreduce procedure times and thus result in better clinical outcomes. Thisis particularly true in the case of stroke patients.

Other aspects and features of the present disclosure will becomeapparent to those of ordinary skill in the art, upon reviewing thefollowing detailed description in conjunction with the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further aspects of this invention are further discussedwith the following description of the accompanying drawings, in whichlike numerals indicate like structural elements and features in variousfigures. The drawings are not necessarily to scale, emphasis insteadbeing placed upon illustrating principles of the invention. The figuresdepict one or more implementations of the inventive devices, by way ofexample only, not by way of limitation. It is expected that those ofskill in the art can conceive of and combining elements from multiplefigures to better suit the needs of the user.

FIGS. 1A-1C are views of the three-catheter system according to aspectsof the present invention;

FIG. 2 shows the system at a target location in the neurovascular with astenotic lesion and an occlusive clot according to aspects of thepresent invention;

FIGS. 3A-3J show cross sections which illustrate the steps of using thesystem to perform a mechanical thrombectomy and stenting procedureaccording to aspects of the present invention;

FIG. 3A illustrates the system at the target site and the microcatheteradvanced across the occlusive clot according to aspects of the presentinvention;

FIG. 3B illustrates the thrombectomy device of the system deployed tocapture an occlusive clot according to aspects of the present invention;

FIG. 3C shows the thrombectomy device and captured clot being withdrawnback inside the system according to aspects of the present invention;

FIG. 3D shows the remainder of the system being advanced to a positionwhere the stenting device is aligned with the lesion according toaspects of the present invention;

FIG. 3E illustrates the outer sheath member being retracted to exposethe stenting device according to aspects of the present invention;

FIG. 3F shows the inflation of the inflation device radially expandingthe stenting device to widen the narrowed vessel according to aspects ofthe present invention;

FIG. 3G shows the continued inflation of the inflation device to widenthe vessel according to aspects of the present invention;

FIG. 3H shows the full desired inflation of the inflation device and thestent embedded in the vessel according to aspects of the presentinvention;

FIG. 3I shows the deflation of the inflation device to release the stentin place according to aspects of the present invention;

FIG. 3J shows the withdrawal of the remainder of the system leaving thestent implanted according to aspects of the present invention;

FIG. 4 is a flow diagram outlining a method for using the system toconduct mechanical thrombectomy and stenting operations according toaspects of the present invention.

DETAILED DESCRIPTION

Specific examples of the present invention are now described in detailwith reference to the Figures, where identical reference numbersindicate elements which are functionally similar or identical. It is anobject of the current invention to offer a system or device which givesthe physician the advantage of operational flexibility to adapt tocomplications or unknowns in an intravascular procedure, such as when anoccluded vessel has a blood clot and also a region of underlyingstenosis which was not detected during angiography. These improvementscan lead to safe and more rapid access to complex areas of theintercranial arteries to remove occlusions and shorten procedure times.

Accessing the various vessels within the vascular, whether they arecoronary, pulmonary, or cerebral, involves well-known procedural stepsand typically the use of a number of conventional,commercially-available accessory products. These products, such asangiographic materials, rotating hemostasis valves, and guidewires arewidely used in laboratory and medical procedures. When these productsare employed in conjunction with the system and methods of thisinvention in the description below, their function and exactconstitution are not described in detail. While the description is inmany cases in the context of treating intercranial arteries, the systemsand devices may be used in other body passageways as well.

Turning to the figures, FIGS. 1A-1C illustrate a system 100 capable oftreating both occlusions and stenosis in a blood vessel. As illustrated,the system 100 can have a first outer guide catheter or sheath member102 having an internal lumen 104. A second deployment catheter 106 canbe disposed in the lumen 104 of the sheath member 102. The sheath member102 can act as a guide catheter for the system 100. The sheath membercan also serve as a deployment sleeve for the deployment catheter,protecting the rest of the system during delivery and deployment.

As illustrated in the cross-sectional view in FIG. 1C, the deploymentcatheter 106 can have a distal end 107, an outer diameter D2, an outersurface 110, an inner lumen 108, and a flexible portion 111 disposedcircumferentially in an annular pattern around the outer surfaceapproximate the distal end. The deployment catheter can also have astepped or depressed region 120 just proximal of the distal end 107 ofthe catheter where the depressed region outer diameter D1 is less thanthe nominal deployment catheter outer diameter D2. The depressed region120 thus can represent a recess or groove-like feature of the deploymentcatheter. The depressed region can take on a trapezoidal shape withshallow corners or could assume a number of other shapes, such as a halfellipse, so long as it is at least partially recessed from the outersurface of the deployment catheter 106 and rings at least a portion ofthe circumference.

An expandable stenting device 112 can be disposed concentrically tocircumscribe the outer circumference of an uninflated inflation device122 and approximate to the flexible portion 111 of the deploymentcatheter 106. The stenting device can be disposed within the flexibleportion of the deployment catheter. In one example, the flexible portion111 extends proximally from the distal end 107 of the deploymentcatheter 106 for a length of approximately 20 cm.

Both the stenting device and the inflation device can circumscribe thedeployment catheter. In one example, the expandable stenting device 112can be a stent having a plurality of resilient metal or plastic strandsformed in a braided pattern. The stenting device can be self-expandingwhen deployed from the system or could be expanded with the aid of theinflation device 122. In one example, this braid of the implantablestent of the stenting device can be of any of a number ofstainless-steel alloys, or of a cobalt or cobalt-chrome alloyconstruction. In other examples, the stent braid can be made ofpolymeric strands.

In still other cases the braid of the stenting device 112 can bemanufactured from Nitinol or a similar superelastic alloy having theshape-memory properties of a tubular structure with a predeterminedouter diameter. A self-expanding stenting device could be actuated byretracting the outer sheath member 102 and might not require a separateinflation device 122 for deployment, but a balloon could still be usedfor pre- or post-dilation of the vessel during the implantation process.This tubular structure can be heat treated on a mandrel to a suitabletemperature to anneal the structure, causing the tube to conform to theshape of the mandrel. In these ways the elastic properties of the stentbraid could be controlled such that the stent can self-expand to aid inthe implantation process. The properties are also important so the stentcan maintain stiffness and strength over the desired lifetime of theimplant. The winding of the braid strands can also be sufficiently denseto provide a stable configuration capable of supporting the full innercircumference of a vessel when implanted.

In another example, the strands or struts of the stent can extendlongitudinally and be woven in a largely helical configuration with thecentral axis or centerline 130 of the resulting tubular structure as acommon axis. A first set of strands can be wound in one direction whilebeing axially displaced from one another. A second group of strandscould be wound in the opposite direction from the first while also beingaxially displaced relative to each other.

The stenting device can also be bare metal or could be coated in anumber of ways. The coating can be hydrophilic or have additiveseffective to increase the lubricity of the mesh braid of the stentingdevice 112 to allow for more atraumatic navigation of the vasculature.In another example, the coating could be hydrogel or include solubleparticles in a polymeric matrix which could soften or fully dissolvewhen exposed to an aqueous medium like blood. In a further example, thecoating could have embedded pharmaceutical agents, such asanti-platelet, anti-coagulant, anti-inflammatory, or anti-microbialagents. These agents could elute from the matrix of the coating whenexposed to aqueous media and help prevent the implanted stent fromforming a potential nidus for future clot formation.

The inflation device 122 can be coupled, glued, or welded to the outersurface 110 of the deployment catheter. The inflation device 122 canhave one or more balloon or innertube-type members of variedconstruction and an expanded condition configured to expand and implantthe stenting device 112. Inflation of the inflation device can beaccomplished through an inflation lumen or tube 124 running the lengthof the deployment catheter 106. The inflation tube can occasionally bean independent member, but more often can be a hollow lumen incorporatedinto the internal construction of the deployment catheter. Theexpandable stenting device and inflation device can togethercircumscribe the depressed region 120 of the deployment catheter 106 andtogether the assembly could have a nominal radial dimension similar tothe nominal outer diameter D2 of the deployment catheter. The depressedregion 120 within the flexible distal section 111 of the deploymentcatheter 106 can be a housing for the inflation device 122 and stentingdevice 112 during delivery of the system 100. The longitudinal length ofdepressed region 120 could be such that the region could accommodate themost common neurovascular stent sizes.

The balloon can be constructed of any of a number of materials, such asChronoprene, Polyurethane, Nylon, PBx, or another thermoplasticelastomer. These materials allow the balloon to be durable and thin. Thefinal shape of the balloon or balloons could be varied and tailored tothe shape of the stenting device 112. In one instance, the balloon couldhave a substantially tubular profile with conical ends.

It should be noted that when an element is described and visualized inthe figures as a tubular structure and generally illustrated as asubstantially right cylindrical structure, when used herein, the terms“tubular” and “tube” are to be construed broadly. They are not meant tobe limited to a structure that is a right cylinder or strictlycircumferential in cross-section or of a uniform cross-sectionthroughout its length.

Also illustrated in FIG. 1C is a microcatheter 114 which can be disposedwithin the lumen 108 of the deployment catheter 106. The microcathetercan be concentric with both the guide/sheath member 102 and deploymentcatheter 106 about the central longitudinal axis 130 of the system 100.The sheath member, deployment catheter, and microcatheter can beindependently moveable with respect to one another. The deploymentcatheter can be used to first aspirate an occlusive clot 50, after whichif necessary, the microcatheter can be used for the delivery anddeployment of a mechanical thrombectomy device 118. The mechanicalthrombectomy device can be any of a number of commercially availableproducts. The device can have a clot retriever with a clot engagingportion having a collapsed delivery configuration within themicrocatheter and be self-expanding to an expanded deployedconfiguration once emerged from the distal tip 115 of the microcatheter.The engaging portion can have an expandable network of struts forgripping the clot and dislodging it from the vessel. The shape of thenetwork can be designed such that when the device 118 is retracted, thestruts exert a force on the clot in a direction substantially parallelto the direction in which the clot 50 is being pulled from the vessel(i.e. substantially parallel to the longitudinal axis 130 of thesystem). This limits the outward radial force applied to the vessel,meaning the action of the thrombectomy device does not serve to increasethe force needed to actually dislodge the clot from the vessel. Thisatraumatic function is important for the often-fragile vessels of theneurovascular 40.

It is of benefit to have the microcatheter 114 and thrombectomy device118 deploy and retract from within the lumen 108 of the deploymentcatheter 106 so clot retrieval process can be kept isolated from and notinterfere with the stenting process. Similarly, a thrombus could beaspirated and retrieved through the inner lumen of the deploymentcatheter without the use of the thrombectomy device.

In some situations, the physician may wish to reverse the flow of bloodin the target vessel. Reversing flow prevents any emboli from migratingdownstream in the vascular. Aspiration can be directed through the lumen104 of the sheath member 102, deployment catheter 106, or both. Toisolate any one catheter lumen of the system for aspiration, a sealcould be formed between the inner and outer surfaces of the catheters.For example, if the aspiration source was connected to the lumen 104 atthe proximal end of the guide sheath 102, suction could be directed tothe mouth at the distal end 107 of the deployment catheter 106 byutilizing a seal of hydrogel between the outer surface 110 of thedeployment catheter and the inner wall of the sheath member. In anotherexample, an expandable member or frame could be used as a flowrestriction between the surfaces. The low-pressure region could therebybe transferred to the distal end 107 of the deployment catheter 106. Insome cases, it may be possible to aspirate a clot or debris directlyinto the lumen 108 of the deployment catheter without the need to usethe microcatheter 114 and thrombectomy device 118.

In another example, a thrombectomy and stenting system 100 for removinga clot from and stenting a neurovascular 40 blood vessel can include asheath member 102, a deployment catheter 106 disposed in a lumen 104 ofthe sheath member, a microcatheter 114 oriented in a lumen 108 of thedeployment catheter, and a thrombectomy device 118 arranged in a lumen116 of the microcatheter. The sheath member 102, deployment catheter106, and microcatheter 114 can be substantially concentric andconfigured to move independently of each other along a longitudinal axisA1. Aspiration for supported procedures can be directed to the mouth atthe distal end 107 of the deployment catheter. The thrombectomy devicecan have an expandable framework of struts or crowns configured to gripand remove an occlusive clot 50.

The outer surface 110 of the deployment catheter 106 can also have adepressed region 120. The depressed region can have a first radialdimension D1 less than a second radial dimension D2 of another region ofthe outer surface adjacent to the depressed region. The deploymentcatheter 106 can have an expandable stenting device 112 coupled to thedeployment catheter outer surface 110. The stenting device cancircumscribe the depressed region 120, such that it is substantiallyradially flush with the outer surface 110. An inflation device 122configured to expand the stenting device 112 can also be included andcoupled to the outer surface of the deployment catheter. In one example,the inflation device is a circumferential balloon that could be inflatedby a contrast liquid media. At least a portion of the stenting device112 can circumscribe the inflation device 122.

FIG. 2 shows the composite system 100 navigated through the internalCarotid artery 30 to a target site within the neurovascular 40. Thetarget site can be a vessel occluded as shown, with an obstructive clotlodged in an area of intercranial stenosis in the form of a lesion 60caused by the buildup of atherosclerotic plaque. An advantage offered bythe system as seen in FIG. 2 is that the guide catheter or sheath member102 of the system can act as a sleeve capable of protecting internalcomponents of the system during navigation to the site. Other designsfor balloon-expandable coronary stents can run the risk of shearing thestent off of the balloon prior to arriving at the target lesion due tothe tortuosity and varied diameters of the cerebral vasculature. This ispart of the reason that considerable effort has been devoted to thedevelopment of low-profile balloon catheters. The recessed or steppedsection 120 as described herein can allow for a more compact system 100to be employed since it enables an outer sheath member 102 of a smallerdiameter to be used while still shielding the system.

FIGS. 3A-3J show cross sections which illustrate example steps of oneway of using a system of the invention to perform a mechanicalthrombectomy and subsequent stenting procedure. When the system 100 isadvanced to a location just proximal to the target lesion 60 andocclusive clot 50, the deployment catheter 106 can be used as anaspiration catheter to aspirate the occlusion into the lumen 108 of thedeployment catheter for removal. For sticker, more obstinateobstructions, the microcatheter 114 can be advanced beyond the distalend 107 of the deployment catheter 106 and across the clot until thedistal end 115 is distal of the clot, as shown in FIG. 3A. A guidewirecould also be used for positioning the microcatheter. In many cases,radiopaque markers or coils can also be added to various portions of thedevice and/or catheter to aid the user in determining when the device isappropriately positioned across the clot. For example, a coil ofradiopaque material, such as tungsten and/or platinum, can be attachedto the distal end of the thrombectomy device so that the terminal endcan be visualized readily during the treatment procedure. Once in theproper position, the thrombectomy device 118 can be unsheathed as themicrocatheter 114 is withdrawn proximally, allowing the thrombectomydevice to expand within and to either side of the clot 50, as shown inFIG. 3B. The scaffold of the capture portion of the device expands togrip portions of the clot.

Once the user is satisfied the thrombectomy device 118 has a firm gripon the clot 50, the device can be withdrawn proximally back in to thedeployment catheter 106, as shown in FIG. 3C. This could be done withthe aid of aspiration through the deployment catheter 106 to helpsustain a firm grip on the clot and avoid fragment loss and migration.If desired, the user can completely remove the thrombectomy device andmicrocatheter from the system 100 and patient to allow for moreefficient aspiration during subsequent steps. Multiple passes with themicrocatheter and thrombectomy device may also be necessary tosufficiently clear the vessel.

After the occlusive clot has been safely secured and withdrawn, theremainder of the system 100 within the sheath member 102 can be advancedacross the stenosis, such that the stenting device 112 and inflationdevice 122 are aligned with the lesion 60, as seen in FIG. 3D. Goodalignment can ensure that the radial force exerted on the vessel whenthey stenting device is expanded is distributed as uniformly as possiblealong the longitudinal length of the device. As with the thrombectomyprocedure from FIG. 3B, proper alignment can be achieved with theplacement of radiopaque markers or coatings. Once aligned across thelesion, the sheath member 102 can be retracted so that the sheath distalend 109 returns proximal to the stenosis to expose the stenting device112, as seen in FIG. 3E.

Once exposed, the stenting device can 112 can self-expand of be radiallyexpanded by the inflation device 122. The inflatable members of theinflation device 122 can be filled with a working fluid, typically acontrast medium, via the inflation lumen or tube 124. Once inflationcommences, the inflation device can radially expand the stenting device112 as illustrated in FIG. 3F. As the inner diameter of the targetvessel is constricted by stenosis, the outer surface of the stentingdevice can first contact the plaque or fatty deposits of the lesion 60.FIG. 3G shows that as the outer diameter of the stenting devicecontinues to grow, this contact can gently exert a compressive radialforce on the lesion by squeezing it between the stenting device andvessel wall. Once the lesion can no longer be further compressed,continued inflation can dilate and enlarge the luminal diameter until adesired implant diameter D3 of the vessel is reached, as demonstrated inFIG. 3H. In one example, this desired diameter is reached when aconstricted first diameter in portion of the vessel containing thelesion increases to 75% of a second diameter in a portion of the vesseladjacent to the first.

In an alternate step, the stenting device 112 can be a self-expandingstructure configured to assume a predetermined outer diameter whendeployed without the need for an inflation device 122. The outerdiameter for the device can be chosen such that a desired radial forceis applied to the vessel and an implant diameter D3 sufficient torecanalize flow.

After the expansion has reopened the occluded neurovascular 40, thestenting device 112 can be left in place as an implanted stent bydeflating the inflation device 122. This could be accomplished byattaching an aspiration source to the proximal end of the inflation tube126. Aspiration could continue until the inflation device had shrunk toa diameter approximate the diameter D2 of the outer surface 110 of thedeployment catheter 106. Alternatively, aspiration could continue untilthe inflation device had shrunk to a diameter less than the insidediameter of the sheath member 102, allowing the deployment catheter tobe retracted into the lumen 104 of the sheath member 102, as shown inFIG. 3I and FIG. 3J. No longer pinned by the inflation device, theexpanded stenting device 112 remains in place as a stent to ensure thepatency of the target vessel lumen.

FIG. 4 is a flow diagram including method steps for administering anintravascular treatment involving thrombectomy and stenting using asystem such as the examples described herein. Referring to method 400outlined in FIG. 4, in step 410 access to a patient's vascular is gainedthrough traditionally-known techniques and a three-catheter system ispositioned approximate a lesion and occlusive clot in an occluded vesselin the neurovascular. The first catheter can be a guide catheter orsheath member as described herein or as would otherwise be known to aperson of ordinary skill in the art. The second catheter can be adelivery catheter with an inflation device and a stenting device asdescribed herein. The delivery catheter can further be configured as anaspiration catheter. The third catheter can be a microcatheter with alumen and a thrombectomy device therein as described herein or as wouldotherwise be known to a person of ordinary skill in the art.

In step 420, a distal portion of the microcatheter and the thrombectomydevice is advanced from the deployment catheter towards and across anocclusive clot in a neurovascular vessel while maintaining thedeployment catheter, inflation device, stenting device, and sheathapproximate the lesion. In step 430, the thrombectomy device is deployedto capture the occlusive clot as illustrated and described herein or byother means, such as direct aspiration, as would be understood by aperson of ordinary skill in the art. Step 430 can also include the stepof retracting the captured clot, thrombectomy device, and microcatheterproximally back in to the lumen of the deployment catheter. The capturedclot, thrombectomy device, and microcatheter can be completely removedfrom the system and patient if desired by the user at this stage.

In step 440, the sheath member, deployment catheter, inflation device,and stenting device are advanced distally across the lesion. Thestenting device can be aligned with the lesion. In step 450, the sheathmember is retracted proximal to the lesion to expose and allow forexpansion of the stenting device.

In step 460, the inflation device is inflated to expand the stentingdevice to dilate the lesion and increase the diameter of the vessellumen. The stenting device can be expanded until a desired stent implantdiameter is reached. In step 470, the inflation device is deflated torelease pressure on the implanted stenting device and allow thedeployment catheter to be withdrawn in to the sheath member. In step480, the stent is left in the vessel as an implant. Step 480 can furtherhave the step of removing the rest of the system from the patient.

The invention is not necessarily limited to the examples described,which can be varied in construction and detail. The terms “distal” and“proximal” are used throughout the preceding description and are meantto refer to a positions and directions relative to a treating physician.As such, “distal” or distally” refer to a position distant to or adirection away from the physician. Similarly, “proximal” or “proximally”refer to a position near to or a direction towards the physician.Furthermore, the singular forms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise.

By “comprising” or “containing” or “including” is meant that at leastthe named compound, element, particle, or method step is present in thecomposition or article or method, but does not exclude the presence ofother compounds, materials, particles, method steps, even if the othersuch compounds, material, particles, method steps have the same functionas what is named.

In describing example embodiments, terminology has been resorted to forthe sake of clarity. It is intended that each term contemplates itsbroadest meaning as understood by those skilled in the art and includesall technical equivalents that operate in a similar manner to accomplisha similar purpose. It is also to be understood that the mention of oneor more steps of a method does not preclude the presence of additionalmethod steps or intervening method steps between those steps expresslyidentified. Some steps of a method can be performed in a different orderthan those described herein without departing from the scope of thedisclosed technology. Similarly, it is also to be understood that themention of one or more components in a device or system does notpreclude the presence of additional components or intervening componentsbetween those components expressly identified. For clarity andconciseness, not all possible combinations have been listed.

As used herein, the terms “about” or “approximately” for any numericalvalues or ranges indicate a suitable dimensional tolerance that allowsthe part or collection of components to function for its intendedpurpose as described herein. More specifically, “about” or“approximately” may refer to the range of values ±20% of the recitedvalue, e.g. “about 90%” may refer to the range of values from 71% to99%.

The descriptions contained herein are examples of embodiments of theinvention and are not intended in any way to limit the scope of theinvention. While particular examples of the present invention aredescribed, various modifications to devices and methods can be madewithout departing from the scope and spirit of the invention. Forexample, while the examples described herein refer to particularcomponents, the invention includes other examples utilizing variouscombinations of components to achieve a described functionality,utilizing alternative materials to achieve a described functionality,combining components from the various examples, combining componentsfrom the various example with known components, etc. The inventioncontemplates substitutions of component parts illustrated herein withother well-known and commercially-available products. To those havingordinary skill in the art to which this invention relates, thesemodifications are often apparent and are intended to be within the scopeof the claims which follow.

1. A thrombectomy and stenting system for removing a clot from a bloodvessel and stenting the blood vessel, the system comprising: a sheathmember comprising a sheath lumen; a deployment catheter oriented withinthe sheath lumen, the deployment catheter comprising a deploymentcatheter lumen and a deployment catheter outer surface; a stentingdevice circumscribing the deployment catheter outer surface; amicrocatheter oriented in the deployment catheter lumen, wherein themicrocatheter comprises a microcatheter lumen; and a thrombectomydevice, wherein at least a portion of the thrombectomy device isoriented in the microcatheter lumen.
 2. The system of claim 1, whereinthe deployment catheter further comprises: a deployment catheter outerdiameter; and a depressed region on the deployment catheter outersurface and proximate to a distal end of the deployment cathetercomprising a depressed region outer diameter configured to be less thanthe deployment catheter outer diameter.
 3. The system of claim 2,wherein the stenting device circumscribes the depressed region of thedeployment catheter.
 4. The system of claim 1, further comprising: aninflation device coupled to the deployment catheter outer surface,wherein a portion of the stenting device circumscribes the inflationdevice, and wherein the inflation device has an expanded conditionconfigured to expand the stenting device.
 5. The system of claim 1,wherein the sheath lumen, the deployment catheter lumen and themicrocatheter lumen are substantially concentric.
 6. The system of claim1, wherein the thrombectomy device comprises an expandable clotretriever collapsible to fit within the microcatheter lumen andself-expandable upon exiting the microcatheter lumen.
 7. The system ofclaim 1, wherein the deployment catheter comprises a flexible portionapproximate the stenting device.
 8. A method of using a thrombectomy andstenting system comprising: a sheath member, a deployment catheter, astenting device comprising an inflation device and a stent, amicrocatheter, and a thrombectomy device, the method comprising:positioning the system approximate a lesion; extending the thrombectomydevice and a distal portion of the microcatheter towards an occlusiveclot in a vasculature while maintaining the deployment catheter, thestenting device, and the sheath approximate the lesion; capturing theocclusive clot with the thrombectomy device; extending the sheathmember, the deployment catheter, and the stenting device to cross thelesion; retracting the sheath member from the lesion; inflating theinflation device of the stenting device across the lesion; and releasingthe stent of the stenting device to cross the lesion.
 9. The method ofclaim 8, further comprising retracting the occlusive clot into thedeployment catheter.
 10. The method of claim 8, further comprisingpositioning the deployment catheter within the sheath lumen.
 11. Themethod of claim 8, further comprising positioning the microcatheterwithin the deployment catheter.
 12. The method of claim 8, furthercomprising positioning the thrombectomy device within the microcatheter.13. The method of claim 8, further comprising disposing the stentingdevice on an outer surface of the deployment catheter.
 14. The method ofclaim 8, wherein inflating the stenting device comprises increasing thediameter of a first portion of a vasculature region comprising thelesion to at least 75% of the diameter of a second portion of thevasculature adjacent to the first portion.
 15. The method of claim 8,further comprising releasing the stent of the stenting device inproximity to the lesion by deflating the inflation device.
 16. Themethod of claim 8, further comprising: crossing the occlusive clot withthe microcatheter and the thrombectomy device; and retracting themicrocatheter while maintaining the thrombectomy device across theocclusive clot.
 17. A thrombectomy and stenting system for removing aclot from a blood vessel and stenting the blood vessel, the systemcomprising: a sheath member comprising a sheath lumen; a deploymentcatheter oriented within the sheath lumen comprising a deploymentcatheter lumen and a deployment catheter outer surface; a stentingdevice coupled to the deployment catheter outer surface; a microcatheteroriented in the deployment catheter lumen, wherein the microcathetercomprises a microcatheter lumen; and a thrombectomy device, wherein atleast a portion the thrombectomy device is oriented in the microcatheterlumen; wherein the sheath member, deployment catheter and microcatheterare substantially concentric and configured to move independently ofeach other along an axis.
 18. The system of claim 17, wherein thedeployment catheter further comprises a depressed region on thedeployment catheter outer surface, wherein the depressed regioncomprises a dimension to be less than a dimension of another region ofthe deployment catheter outer surface adjacent to the depressed region.19. The system of claim 18, wherein the stenting device circumscribesthe depressed region of the deployment catheter.
 20. The system of claim17, further comprising: an inflation device coupled to the deploymentcatheter outer surface, wherein a portion of the stenting devicecircumscribes the inflation device.